efather

I am trying to test my engine and all related areas (finally). I notice my temp gauge is creeping up and up until I turn off the engine and let it cool down.

I really cannot tell if it is a temp sender issue, gauge issue or issue with the switch in the radiator (possibly grounding issue). Whats the best approach for isolating the issue?

My 1st guess is that the radiator is not grounded well, but I am not sure how to test that theory. Is there a way to get the fans to come on with the switch in just the on position instead of letting the temp switch turn them on. I think that would tell me if it is not grounded right. The switch wire I added to the fuse box works fine otherwise the car would not start since it is what I use to turn on the AL-6.

The radiator is getting hot, so the water is flowing through the block and back into the radiator. I dont really doubt this cause it sucked most of the water out of the radiator into the blcok and I had to refill it during initial firing. plus the water pump and thermostat is brand new.

langg

I had a problem when I first installed my Dewitts setup. I had not grounded the radiator. I put a ground strap from the bracket on the radiator to steel structure beside the radiator (not the rad support). Worked fine after that.

mrvette

I have Dual Spals from DeWitt, and so each fan has a red and black wire, I put the two black wired to the frame/cross member on a dedicated screw/eyelet, the two red wires go to the power relay on top of the housing just in front of the alternator, power to the relay goes through a 3 amp blade fuse right to the alternator output stud, the relay is controlled by one end of the coil going to a switched hot, such as the yellow wiper wire on the plug at the motor.... the other end of the relay coil is computer controlled on my car, but anything that grounds it should close the relay and fire off the fans.....

0Tom@Dewitt

Just ground the grey sensor wire, fans should come on

efather

I tried to ground it to the radiator support. the yellows ran to a power stud that comes off the main battery terminal as a junction box. Obviously the gray to the switch, and finally the last one went to the ign wire that I added to turn on the AL-6.

efather

I unhooked the gray wire and grounded it as tom suggested and the fans came on just fine, without any moving of any grounds, so that does not look like the issues.

I will try the temperature sender next to see if that is the issue, since the gauge moves and I don't remember it being broke when I took it all apart.

If I need to replace the switch in the radiator is there a recommended one to use?

Is there a way to prove that water is truly pumping through the system and that the water is heating up enough to trip that switch in the radiator? like I said water pump, thermostat are all new so those really should not be the issue.

Is there a way to find the true temp of the water in the radiator or of the engine itself?

MIKE80

Is the radiator itself grounded? Not just the radiator support.

efather

The wire off the radiator at the bottom is grounded to the same location as the relays were grounded (lower part of the radiator support). Is that the grounding point you are referring to?

ill try to move that ground somewhere else and see if that helps. Did not occur to me that that grounding may be the cause. I was focused on the relays not being grounded because I assumed the ground point was going to be fine since the relays worked and they are in the same spot.

MIKE80

Might be a good idea to run a ground wire from that ground point you are using on the radiator support, to the frame.

efather

I moved the radiator ground to be the same location that the inginition and engine is grounded. so I know it is grounded properly now, but the fan still does not come on.

I let the car run, the temp slowly climb, when the gauge hit 210 I expected the fans to come on, but nothing, it kept climbing until I turned it off just before red line.

The upper hose got real hot when it got above 220/225, the lower hose stayed warm not hot. The radiator got hot also.

I know the thermostat wont open until temp is enough, but I am sure 200 range it should pop open, and to me the fan should come on soon there after.

Other than the fans not coming on is there any other things that raise a red flag??

MIKE80

Sounds like the temperature sensor is not working. You can try connecting a meter up to the sensor to check for ground. You should see no ground until the temperature sensor get's hot and makes the contact for the ground connection. My fans come on before 200 degrees. If you do not see a ground at the sensor by 200 degrees, I'd say the sensor is bad and call Dewitts for a replacement.

I just added a manual switch to my fans for when I run my air conditioning to cool the condensor.

http://forums.corvetteforum.com/c3-t...spal-fans.html